Completely pneumatic suspension device for a towed, vibrating tamping road roller



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Jan. 29, 1963 D. DOMENIGHETTI COMPLETELY PNEUMATIC SUSPENSION DEVICE FOR A TOWED, VIBRATING TAMPING ROAD ROLLER Filed Aug. 25, 1959 hWtWTOk 190 E NI c0 'DOMENIG-H & Tr!

ATTORNH United States Patent ()fiice 3,075,437 Patented Jan. 29, 1953 3,075,437 COMPLETELY PNEUIWATEC SUSPENMUN DEVECE FOR A TUWED, VEBRATING TAlViPENG ROAD ROLLER The conventional vibrating tamping rollers essentially consist as shown in FIG. 1 of a frame 1, the fore part of which carries a hook for the towing, while the re mainder bears a vibrating drum 3, an engine 4 designed to drive the vibration exciter, which last is usually disposed in the inside of the Vibrating drum.

The vibrating drum 3 is usually mounted on the frame 1 by means of a damping system 5 consenting free oscillation and vibration to the drum 3 without transmitting however these two movements to the frame 1 and to the members coupled thereto.

These conventional damping systems used up to now consists in solid rubber elements which, being rapidly worn out and heated, loose their good properties, undergo changes in their elastic coefiicient, are diificult to be replaced and are very expensive. Furthermore these damping systems are usually polary isotropic i.e. for equal displacements from their rest, or equilibrium positions they practically oppose the same resistance in which ever direction the vibrating drum is displaced.

It has been proven very useful to have a suspension and damping system for the vibrating drum which has a different elastic coefiicient depending on the angular direction of the radial displacement undergone by the vibrating drum during its vibratory motion.

The present invention relates to a suspension system comprising as elastic elements pneumatic rings, containing in their inner part a gas which, because of the rapid succession of stresses the said rings are subjected to, behaves practically adiabatically, thus having a minimum loss of vibrating energy into heat.

The said pneumatic rings are furthermore so fixed to the frame at one side and to the vibrating member at the other side that they react with forces of different magnitudes depending on the direction of the radial displacements of the vibrating drum.

The accompanying drawing shows by way of example only, some embodiments of the invention and namely:

FIG. 1 is a diagrammatic side view of a conventional towed vibrating tamping roller.

FIG. 2 is an embodiment of the pneumatic suspension according to the present invention.

FIG. 3 is a further embodiment of the said suspension.

As shown in FIG. 2 the drum 6 is mounted on the main frame 7 by means of a bearing 8 surrounding a pneumatic ring 9, the rim it of which is revolvingly mounted on the shaft 11 of the vibrating drum 6. An auxiliary frame 12 is further rigidly mounted on the main frame 7, said frame 12 carrying bearings 13 apt to receive a shaft 14, supporting pneumatic rings 15 that are so disposed as to press on the outer surface of the vibrating drum 6.

The geometric plane X-Y containing the two axe of the vibrating drum 6 and of the shaft 14 may either be vertical or inclined at will. This particular disposition provides that a displacement of the vibrating drum 6 whereby the drum 6 approaches the axis 14 generates an elastic reaction of the system greater than the one generated by a drum displacement of the same magnitude but so directed as to widen the distance between the drum 6 and the shaft i4.

Practically, by examining the behavior of the drum 6 during one of its vibratory oscillations about its equilibrium point taking place in the vertical plane for instance, it will be noted that during the upward phase of the said oscillation the vibratory energy of the drum is partly stored without substantial losses in the pneumatic rings 15 or rather in the gases contained therein, which approximately undergo an adiabatic compression, while in the downward phase of the oscillation the said energy is returned also practically without any substantial losses to the vibrating drum which discharges it to the ground to be tamped together with the vibratory energy relative to the downward phase.

In the embodiment of FIG. 3 two shafts 14, 14' are provided, each having a series of adjacent tires 15 mounted on an auxiliary frame 12 and pressing against the outer surface of the drum 6.

The planes XY' and X"- formed by the geo metric axes of the shaft 11 of the drum 6 and respectively of the shafts 14, 14' may have any desired inclination with respect to the normal thus realizing an anisotropic suspension system otfering the same advantages as the sys ternrelating to FIG. 2.

What we claim is:

1. In a pneumatic suspension device for a tamping road roller having a motor, the combination of a vibrating drum, vibrating means in said drum, coupled to said motor, first pneumatic rings co-axial with the axis of rotation of said vibrating drum, with a non-vibrating frame comprising a main horizontal part supporting said motor and being supported by said vibrating drum, a secondary arched part forming a bridge on said main part, fixedly connected to the latter, said main part being supported by said vibrating drum through said first pneumatic rings, and at least one second pneumatic ring tangent to the outer surface of said vibrating drum said second ring rotatably mounted on a shaft arranged on said secondary arched part of said non-vibrating frame approximately vertically on top of said drum.

2. In a pneumatic suspension device for a tamping road roller having a motor, the combination of a vibrating drum, vibrating means in said drum, coupled to said mo tor, first pneumatic rings co-axial with the axis of rotation of said vibrating drum, with a non-vibrating frame comprising a main horizontal part supporting said motor and being supported by said vibrating drum, a secondary arched par-t forming a bridge on said main part, fixedly connected to the latter but not touching said vibrating drum, said main part being supported by said vibrating drum through said first pneumatic rings, and a plurality of second pneumatic rings tangent to the outer surface of said vibrating drum, said second rings rotatably mounted on a plurality of shafts arranged at various points of said secondary arched part of said non-vibrating frame.

3. In a pneumatic suspension device for a tamping road roller having a motor, the combination of a vibrating drum, vibrating means in said drum, coupled to said motor, first pneumatic rings co-axial with the axis of rotation of said vibrating drum, with a non vibrating frame comprising a main horizontal part supporting said motor and being supported by said vibrating drum, a secondary arched part forming a bridge on said main part, fixedly connected to the latter but not touching said vibrating drum, said main part being supported by said vibrating drum through said firs-t pneumatic rings, and a plurality of second pneumatic rings tangent to the outer surface of said vibrating drum said second rings rotatably mounted on a plurality of shafts arranged at various points of said secondary arched part of said non-vibrating frame, each 3 one of sid plurality of shafts on said secondary arched 2,812,696 part of said non-vibrating frame sup orting a plurality of 2,933,354 said second pneumatic rings.

References Cited in the file of this patent 5 143,961 UNITED STATES PATENTS 1,101,776 1,935,950 Lawrence Nov. 21, 1933 331,772 2,704,968 Paramythioti Mar. 29, 1955 4 Henry Nov. 12, 1957 Pri'meau Apr. 19, 1960 FOREIGN PATENTS Australia Oct. 25, 1951 France Apr. 27, 1955 Switzerland Sept. 30, 1958 

1. IN A PNEUMATIC SUSPENSION DEVICE FOR A TAMPING ROAD ROLLER HAVING A MOTOR, THE COMBINATION OF A VIBRATING DRUM, VIBRATING MEANS IN SAID DRUM, COUPLED TO SAID MOTOR, FIRST PNEUMATIC RINGS CO-AXIAL WITH THE AXIS OF ROTATION OF SAID VIBRATING DRUM, WITH A NON-VIBRATING FRAME COMPRISING A MAIN HORIZONTAL PART SUPPORTING SAID MOTOR AND BEING SUPPORTED BY SAID VIBRATING DRUM, A SECONDARY ARCHED PART FORMING A BRIDGE ON SAID MAIN PART, FIXEDLY CONNECTED TO THE LATTER, SAID MAIN PART BEING SUPPORTED BY SAID VIBRATING DRUM THROUGH SAID FIRST PNEUMATIC RINGS, AND AT LEAST ONE SECOND PNEUMATIC RING TANGENT TO THE OUTER SURFACE OF SAID VIBRATING DRUM SAID SECOND RING ROTATABLY MOUNTED ON A SHAFT ARRANGED ON SAID SECONDARY ARCHED PART OF SAID NON-VIBRATING FRAME APPROXIMATELY VERTICALLY ON TOP OF SAID DRUM. 